Flight in factory

ABSTRACT

The invention relates to methods of measuring an aircraft under simulated flight-loads while the aircraft is not in-flight. While the aircraft is under the simulated flight-loads, positions of one or more portions of the aircraft may be measured in order to determine how the aircraft is performing under such loads. The aircraft may be readjusted and/or redesigned based on the measurements in order to reduce drag on the aircraft.

BACKGROUND OF THE INVENTION

It is important to determine how an aircraft will perform in flightconditions in order to determine whether drag on the aircraft can bereduced. Many prior art methods measure expected aircraft in-flightperformance, such as the deflections of the wings, by testing theaircraft while in flight. The prior art methods may experience one ormore problems such as difficulty in measuring the aircraft while in theair, prolonged time to conduct testing of the aircraft during flight,and difficulties experienced during flight, amongst other types ofproblems.

A method of measuring an aircraft under simulated flight-loads, whilethe aircraft is not in flight, is needed which may solve or reduce oneor more problems associated with one or more of the prior art in-flightmeasuring methods.

SUMMARY OF THE INVENTION

In one aspect of the invention, a method of measuring an aircraft undersimulated flight-loads while not in flight is provided. In one step,simulated flight-loads are applied to the aircraft while the aircraft isnot in flight in order to substantially simulate loads on the aircraftduring flight. In another step, a position of one or more portions ofthe aircraft is measured while under the simulated flight-loads.

In another aspect of the invention, another method of measuring anaircraft under simulated flight-loads while not in flight is provided.In one step, expected flight-loads on the aircraft are determined inorder to approximate loads the aircraft experiences while in flight. Inanother step, the expected flight-loads are applied to the aircraftwhile the aircraft is not in flight in order to simulate flight. Instill another step, the aircraft is measured while under the expectedflight-loads.

In a further aspect of the invention, an aircraft is provided. When theaircraft was not in flight simulated flight-loads were applied to theaircraft to substantially simulate loads on the aircraft during flight.The aircraft was measured while under the simulated flight-loads.

These and other features, aspects and advantages of the invention willbecome better understood with reference to the following drawings,description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a flowchart showing a method of measuring an aircraftunder one embodiment of the invention;

FIG. 2 depicts a side view of an aircraft being supported by cradledevices under one embodiment of the invention;

FIG. 3 depicts a partial perspective view of a surface of one cradledevice under another embodiment of the invention; and

FIG. 4 depicts a top view of an aircraft being measured under yetanother embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description is of the best currently contemplatedmodes of carrying out the invention. The description is not to be takenin a limiting sense, but is made merely for the purpose of illustratingthe general principles of the invention, since the scope of theinvention is best defined by the appended claims.

As shown in FIG. 1, in one embodiment of the invention, a method 10 ofmeasuring an aircraft, while the aircraft is not in flight and undersimulated flight-loads, is provided. In one step 12, simulatedflight-loads may be applied to the aircraft while the aircraft is not inflight. The simulated flight-loads may substantially simulate loads onthe aircraft during flight, and may be in the amount of 1 g or in otheramounts. The simulated flight-loads may have been determined, or may bedetermined, by flying a second aircraft having pressure sensors whichdetected and/or recorded actual flight-loads. The pressure sensors mayhave been located on the wings of the aircraft and/or on other parts ofthe aircraft in order to determine the pressure amounts over variousportions of the aircraft at various times. This flight-load data mayhave been sent to one or more computers which stored the flight-loaddata for various portions of the aircraft. The determined flight-loaddata of the second aircraft, which may be referred to as the expectedflight-loads of the aircraft being tested, may then be used in order toapply substantially the same simulated flight-loads to the aircraftbeing tested. For instance, the same pressure loading distribution whichoccurred to the second aircraft during flight may be applied in the samedistribution and time interval over the aircraft being tested. In suchmanner, the aircraft may be tested with real-life flight-loads.

In another embodiment, the simulated flight-loads applied to theaircraft being tested may comprise loads determined by a computer model,which may also be referred to as the expected flight-loads of theaircraft. For instance, a computer may be used to determine expectedflight-loads on the aircraft being tested. The computer determinedexpected flight-loads may then be applied as simulated flight-loads tothe aircraft being tested in order to test the aircraft under theexpected loading conditions. It should be noted that the expectedflight-loads of the aircraft being tested may comprise the expectedflight-loads of the aircraft during flight, and as discussed, may bedetermined through actual flight measurements of another aircraft, ormay be determined through a computer model to predict the aircraft'sflight-loads. In one embodiment, the simulated flight-loads applied tothe aircraft may comprise the determined expected flight-loads of theaircraft.

As shown in FIG. 2, in order to apply the simulated flight-loads to theaircraft, one or more cradle devices 14 may be utilized. While theaircraft 18 is supported on its own landing gear, on a ground surface ina factory or hangar, with simulated passenger, crew, and cargo weight,one or more cradle devices 14 may be placed under each wing 16 of theaircraft 18 in a variety of configurations, positions, and locations. Inone embodiment, each wing 16 of the aircraft 18 may have four zones ofcradle devices 14 distributed over the wings 16. Each cradle device 14may comprise wheels 20, jack 22, support members 24, and support surface23. The wheels 20 may be utilized to move the cradle devices 14 intoplace under the aircraft wings 16. The support surface 23 supported bythe support members 24 may be placed underneath the wings 16 of theaircraft 18. The jacks 22 may be utilized to increase the height of thesupport surface 23 to force the wings 16 in upwardly directions 26. Insuch manner, the aircraft 18 may be raised off the ground so that theaircraft 18 may be fully supported by the cradle devices 14 which arelocated on ground surface 25. The jacks 22 may be motor drivenball-screw jacks, or of other types. Each jack 22 may be equipped withposition and force feedback devices. Movement of each jack 22 may becontrolled by a computerized control system to enable application ofloads necessary to simulate flying conditions, such as transient takeoff loads. While supported by the cradle devices 14, the weight of theaircraft 18 may include passengers, crew, and cargo, similar to maximumdesign landing weight. In other embodiments, the weight of the aircraft18 may be in varying amounts.

Additionally, at the same time the one or more cradle devices 14 areplaced against the wings 16 of the aircraft 18, one or more other cradledevices 28 may be placed against the horizontal stabilizers 30 of theaircraft 18 in a variety of configurations, positions, and locations. Inone embodiment, one cradle device 28 is applied against each of the leftand right horizontal stabilizers 30. The cradle devices 28 may force thehorizontal stabilizers 30 in a downward direction 32, while the cradledevices 14 may force the wings 16 in an upward direction 26, in order tosubstantially simulate loads on the aircraft 18 during flight. Thedownward force applied to the horizontal stabilizers 30 by the cradledevices 28 may act as a counterbalance to offset the upward forceapplied to the wings 16 by the cradle devices 14.

Support surfaces 23 of the cradle devices 14 and 28 may comprise airchambers 36 as shown in FIGS. 2 and 3. As shown in FIG. 3, ribbedsurfaces 38 may surround the air chambers 36 which may contain pressuresensors 40 and air holes 42. Support surfaces 23 may abut against theaircraft 18 when the cradle devices 14 and 28 are put into place. Thewings 16 of the aircraft 18 may rest against the ribbed surfaces 38 ofthe cradle devices 14, which may be made of Teflon, Rubber, or othermaterials. Air pressure may be forced through the air holes 42 of thecradle devices 14 into the air chambers 36, in order to form a thincushion air wall forcing and supporting the wings 16 of the aircraft 18upwardly, thereby lifting the aircraft 18 off the ground. The airpressure distribution over the wings 16 of the aircraft 18 may beadjusted in each cradle device zone in order to apply simulatedflight-loads on the aircraft 18. The pressure sensors 40 may measure theapplied pressure within the air chambers in order to regulate pressuredistribution over the aircraft 18. Pressure in the amount of threepounds per square inch may be applied. In other embodiments, varyingamounts of pressure may be applied. For instance, in another embodiment,pressure may be applied in the range of one to ten pounds per squareinch. In still other embodiments, varying ranges of pressure may beapplied. The air chambers 36 of the cradle devices 28 disposed againstthe horizontal stabilizers 30 may function in the same manner in orderto force the horizontal stabilizers 30 in a downward direction utilizingair pressure. In such manner, simulated flight-loads may be applied tothe aircraft 18 utilizing the cradle devices 14 and 28.

The cradle devices 14 and 28 may be connected to one or more computers.The computers may control the movements, positions, and loads applied tothe aircraft 18 by the cradle devices 14 and 28. As a result, precise,simulated loads may be applied in the appropriate locations, times,durations, and amounts over the aircraft 18 in order to substantiallysimulate flight-loads on the aircraft 18 without the aircraft 18 beingin flight.

As shown in FIG. 1, in another step 44 of the method 10, a position ofone or more portions of the aircraft 18, such as the deflections ofvarious portions of the aircraft 18 such as the wings 16, may bemeasured while the aircraft 18 is not in flight and under the simulatedflight-loads, which may comprise the expected flight-loads of theaircraft 18. During this step, as shown in FIGS. 2 and 4, a lasertracking device 46 may be placed in front of the nose of the aircraft18, laser tracking devices 50 and 52 may be placed to the left and rightof the aircraft 18, and laser tracking devices 54 and 56 may be placedinside open doors of the aircraft 18. The laser tracking devices (i.e.laser trackers) may be networked together, and may be controlled bycomputers and/or software, such as New River Kinematics Spatial Analyzersoftware.

Two targets 58 and 60 may be attached to the nose of the aircraft 18.Two targets 62 and 64 may be attached to the outboard aileron of theright wing of the aircraft 18, while two other targets 66 and 68 may beattached to the outboard aileron of the left wing of the aircraft 18.Similarly, two targets 70 and 72 may be attached to the right hand siderudder hinge line of the aircraft 18, while two other targets 74 and 76may be attached to the left hand side rudder hinge line of the aircraft18. Each of targets 58, 60, 62, 64, 66, 68, 70, 72, 74, and 76 maycomprise combination laser and photogrammetry targets as described inU.S. patent application Ser. No. 11/437,201, titled Combination LaserAnd Photogrammetry Target, filed on May 19, 2006, which is herebyincorporated by reference. Each of the targets may comprise a firstportion adapted to reflect a laser beam towards a laser tracker, and asecond portion adapted to reflect a light beam towards a photogrammetrycamera.

A central controller (not shown) may initiate the application ofsimulated flight-loads to the aircraft 18 by causing the cradle devices14 and 28 to lift the aircraft 18 off the ground, thereby simulatingflight. At this point, the laser tracking devices 46, 50, 52, 54, and 56may acquire the positions of the targets 58, 60, 62, 64, 66, 68, 70, 72,74, and 76 by reflecting a laser beam off the targets to determine theirX, Y, and Z spatial coordinates relative to the tracking devices.

As shown in FIG. 4, two mobile measurement systems 78 and 80 may beplaced on each side of the rear of the aircraft 18. Each mobilemeasurement system 78 and 80 may comprise two photogrammetry cameras,one pro-spot projector, one automated guided vehicle, one automatedrobot, and twelve targets. The automated guided vehicles may beconnected to one or more computers which may guide the vehicles inpre-determined patterns 77 and 79 around the sides of the aircraft 18.The automated robots may comprise motorized scissor lifts having roboticarms, each holding two photogrammetry cameras and a pro-spot projector.In other embodiments, other equipment may be added to the automatedscanning robots such as conventional or still cameras, laser scanners,ultrasonic scanners, X-ray devices, and other types of apparatus. At alltimes, at least one side of each mobile measurement system 78 and 80 maybe visible and in communication with at least one of the networked lasertracking devices 46, 50, 52, 54, and 56. In such manner, the lasertracking devices 46, 50, 52, 54, and 56 may keep track of the positionof each mobile measurement system 78 and 80 by reflecting laser beamsoff of one or more of the twelve targets attached to each mobile system78 and 80 in order to determine the spatial X, Y, and Z location of eachmobile system 78 and 80 as they travel around the aircraft 18 in theirpre-determined patterns.

The mobile systems 78 and 80 may move to approximately seventy-fivescanning/photographing locations around the periphery of the left andright sides of the aircraft 18. In each of the seventy-five locations,the scissor lifts having robotic arms, each holding two photogrammetrycameras and a pro-spot projector, may scan and photograph the left andrights sides of the aircraft 18 utilizing the process detailed in U.S.patent application Ser. No. 11/432,061, titled Laser And PhotogrammetryMerged Process, filed on May 10, 2006, which is hereby incorporated byreference, in order to take measurements of the aircraft 18 usingphotogrammetry. The pro-spot projector on each mobile system 78 and 80may provide an array of projected dots which are targets for thephotogrammetry cameras. At each of the seventy-five locations, the robotmay position the cameras and pro-spot projector in several differentattitudes to provide substantial coverage of the aircraft's outersurface, in order to take photogrammetry pictures of the projected dottargets over a substantial portion of the aircraft. This may allow formeasurement of surfaces of interest, such as high lifts, doors, andcontrol surfaces. Spatial analyzer software may control the movement ofthe automated scissor lifts and the measurement sequences.

The camera images may be merged wirelessly and may be controlledutilizing GSI's V-Stars photogrammetry software. The digital datapositions of the targets may be acquired by the laser trackers. Thisdata may be sent to the V-Stars to assist with the transformation of thetarget location data which may be merged with the camera image/positiondata. In such manner, the photogrammetry data obtained at theseventy-five locations may be referenced with respect to the locationsof the ten targets distributed over the aircraft. This combined data maythen be sent to the Spatial Analyzer and V-Stars for final bundling inorder to determine final airplane shape definition data. One or morecomputers may then determine the locations/positions/measurements ofvarious portions of the aircraft in order to determine how the simulatedflight-loads are affecting the aircraft. In such manner, the deflectionsof the aircraft, such as the deflections of the wings, may be determinedduring simulated flight.

After completing the measurement process, the central controller maylower the aircraft back on its landing gear. The measurement data may beprocessed by computers and compared to a reference, such as a CAD modelor wind tunnel measurements. Based on the measured position data of theaircraft during the simulated flight, drag measurements may bedetermined. The measured aircraft may be compared with a computationalfluid dynamic model of the theoretical perfect aircraft. The errors inshape of the measured aircraft may be determined in order to readjustand/or change the aircraft design and/or structure in order to reducedrag on the aircraft. The reduction of drag on the aircraft may savemoney in reduced fuel, may reduce wear, tear, and fatigue on theaircraft, and may reduce travel times.

In other embodiments, any number, type, size, location, andconfiguration of laser tracking devices, targets, mobile measurementsystems, photogrammetry cameras, pro-spot projectors, automated guidedvehicles, automated robots, software, and/or computers may be utilizedto measure one or more portions of the aircraft while under simulatedflight-loads.

In yet another embodiment of the invention, an aircraft may be provided.When the aircraft was not in flight, simulated flight-loads may havebeen applied to the aircraft to substantially simulate loads on theaircraft during flight. The aircraft may have been measured while underthe simulated flight-loads. In another embodiment, the aircraft may havebeen readjusted to reduce drag based on data measured while under thesimulated flight-loads.

It should be understood, of course, that the foregoing relates toexemplary embodiments of the invention and that modifications may bemade without departing from the spirit and scope of the invention as setforth in the following claims.

1. A method of measuring an aircraft under simulated flight-loads whilenot in flight comprising: applying simulated flight-loads to saidaircraft while said aircraft is not in flight in order to substantiallysimulate loads on said aircraft during flight; and measuring a positionof one or more portions of said aircraft while under said simulatedflight-loads.
 2. The method of claim 1 wherein said simulatedflight-loads are determined by measuring actual flight-loads of a secondaircraft during flight.
 3. The method of claim 2 wherein said actualflight-loads are determined utilizing pressure sensing devices on saidsecond aircraft during flight.
 4. The method of claim 3 wherein saidpressure sensing devices deliver data to one or more computers.
 5. Themethod of claim 1 wherein said simulated flight-loads comprise loadsdetermined by a computer model.
 6. The method of claim 1 wherein thestep of applying simulated flight-loads comprises lifting said aircraftoff said ground utilizing one or more cradle devices, and applying saidsimulated flight-loads to said aircraft utilizing said one or morecradle devices.
 7. The method of claim 6 wherein said one or more cradledevices comprise one or more jacks.
 8. The method of claim 6 whereinsaid one or more cradle devices apply said simulated flight-loads tosaid aircraft utilizing one or more air chambers which force air ontosaid aircraft.
 9. The method of claim 6 wherein said one or more cradledevices are applied to wings of said aircraft, and said one or morecradle devices force said wings in upwardly directions.
 10. The methodof claim 6 wherein another cradle device is applied to a horizontalstabilizer of said aircraft, and said another cradle device forces saidhorizontal stabilizer in a downwardly direction.
 11. The method of claim1 wherein the step of measuring utilizes at least one target, lasertracker, photogrammetry camera, and light-projector.
 12. The method ofclaim 11 wherein said at least one target comprises a first portionadapted to reflect a laser beam towards said laser tracker and a secondportion adapted to reflect a light beam towards said photogrammetrycamera.
 13. The method of claim 12 wherein a plurality of said targetsare distributed on said aircraft.
 14. The method of claim 12 wherein aplurality of said laser trackers are distributed around said aircraft.15. The method of claim 12 further comprising at least one mobilemeasurement system.
 16. The method of claim 15 wherein said at least onemobile measurement system comprises an automated guided vehicle, arobot, said photogrammetry camera, said light-projector, and saidtarget.
 17. The method of claim 16 wherein said at least one automatedguided vehicle travels around said aircraft.
 18. The method of claim 12wherein deflections of wings of said aircraft, while said aircraft isunder said simulated flight-loads, are measured utilizing multipletargets.
 19. The method of claim 1 wherein the step of measuringutilizes one or more computers.
 20. The method of claim 1 furthercomprising the step of utilizing position data obtained during themeasuring step in order to readjust said aircraft to reduce drag.
 21. Amethod of measuring an aircraft under simulated flight-loads while notin flight comprising: determining expected flight-loads on said aircraftto approximate loads said aircraft experiences while in flight; applyingsaid expected flight-loads to said aircraft while said aircraft is notin flight in order to simulate flight; and measuring said aircraft whileunder said expected flight-loads.
 22. The method of claim 21 wherein thestep of determining expected flight-loads on said aircraft comprises atleast one of measuring actual flight-loads of a second aircraft duringflight and utilizing a computer model.
 23. The method of claim 21wherein the step of applying said expected flight-loads compriseslifting said aircraft off a ground surface utilizing a plurality ofcradle devices, and applying air pressure on said aircraft in the amountand location of said expected flight-loads utilizing said cradledevices.
 24. The method of claim 21 wherein the step of measuring saidaircraft comprises the use of a target, a laser tracker, aphotogrammetry camera, and a light-projector.
 25. The method of claim 24wherein said target comprises a first portion adapted to reflect a laserbeam towards said laser tracker and a second portion adapted to reflecta light beam towards said photogrammetry camera.
 26. The method of claim21 wherein the step of measuring utilizes one or more computers.
 27. Themethod of claim 21 further comprising the step of utilizing positiondata obtained during the measuring step in order to readjust saidaircraft to reduce drag.
 28. An aircraft wherein when said aircraft wasnot in flight simulated flight-loads were applied to said aircraft tosubstantially simulate loads on said aircraft during flight, and saidaircraft was measured while under said simulated flight-loads.
 29. Theaircraft of claim 28 wherein said aircraft was readjusted based on datameasured while under said simulated flight-loads to reduce drag.